1. Technical Field
The present invention relates to an apparatus with a position detection function which optically detects the position of a target object located on the side of a surface from which information is viewed.
2. Related Art
As an optical position detecting device which optically detects a target object, for example, as shown in FIG. 15, an optical position detecting device is suggested in which detection light L2 is emitted toward the target object Ob via a translucent member 90 from two light source sections 12 for detection, and detection light L3 reflected by the target object Ob is transmitted through the translucent member 90 and is detected by a light detection section 30. In this optical position detecting device, for example, if the two light source sections 12 for detection are differentially moved on the basis of a detection result in the light detection section 30, the ratio of the distance between one light source section 12 for detection of the two light source sections 12 for detection and the target object Ob and the distance between the other light source section 12 for detection and the target object Ob is known. Accordingly, the position of the target object Ob can be detected (refer to JP-T-2003-534554 (FIG. 10)).
However, in the configuration shown in FIG. 15, in a case where the target object Ob is inside two light source sections 12 for detection as shown as the target object Ob1 and in a case where the target object Ob is outside the two light source sections 12 for detection as shown as the target object Ob2, there is a problem in that the ratio of the distance between one light source section 12 for detection of the two light source sections 12 for detection and the target object Ob and the distance between the other light source section 12 for detection and the target object Ob becomes equal. For this reason, when the ratio of the distance between one light source section 12 for detection of the two light source sections 12 for detection and the target object Ob and the distance between the other light source section 12 for detection and the target object Ob is obtained, it cannot be distinguished whether the distance between the two light source sections 12 for detection may be internally divided or externally divided.